2024, Vol. 6, Issue 11, Part B

Various types of contact lens present world-wide which are used to make spectacle free. Globally, approx. 140 million contact lens users are present. Actually, contact lens is foreign body respected of ocular surface, but a lot of benefits presents associated with disadvantages.

Extended using time of contact lens can feel discomfort on ocular surface, then there is a temporary solution of using topical lubricating eye drop. Some types of conjunctival complications ^[1] are present like giant papillary conjunctivitis (GPC), allergic conjunctivitis etc. For complications related of contact lens wear at cornea like epithelial oedema, bacterial keratitis ^{[8, 9, 10]}, fungal keratitis ^{[6, 7]}, microcysts, corneal neovascularization, peripheral corneal staining, corneal abrasions, superficial punctate keratitis etc ^{[2, 3]}. Long time of using contact lens can decreases the oxygen permeability of cornea, that is induces the hypoxia condition of cornea. The high risk of hypoxia is corneal oedema along with corneal infection.

But using contact lenses means that a foreign object is constantly pressed against the cornea, which can change the cornea's architecture and physiology ^[5]. Long-term lens use can lead to corneal hypoxia, which can collect fluid in the stroma. Several researchers have shown morphologic alterations in the corneal endothelium cells of people who wear a variety of contact lens types, including soft, hard, and extended wear soft lenses. These alterations might be a sign of persistent hypoxia-induced cell stress, which raises carbon dioxide levels, causes lactate to build up, and alters pH. Polymegathism may be a sign of abnormal cell function, and pleomorphism may be a sensitive measure of the condition of the corneal endothelium ^[4].

This article focused on corneal oxygenation, epithelial integrity, tear film stability, and the prevalence of corneal complications such as microbial keratitis and corneal neovascularization. Additionally, the study analysed the role of different contact lens materials, including silicone hydrogel and hydrogel lenses, in reducing hypoxic stress and promoting corneal health during extended wear. Wearing contact lenses for extended periods of time increases the risk of hypoxia and decreased oxygen delivery to the cornea. Even though silicone hydrogel contact lens technology has increased oxygen permeability and decreased the frequency of hypoxia-related problems, extended contact lens wear still carries a significant risk of neovascularisation and corneal infections. As a result, it's critical that both contact lens wearers and eye care specialists are aware of these hazards, stress the need of taking good care of your lenses, and weigh the advantages of wearing your lenses for shorter periods of time. Innovative lens designs and materials that can better maintain ocular health during prolonged usage require more investigation.